LNT Desulfurization Timing via DPF Regeneration Count
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Solution Overview
Problem
Conventional desulfurization methods for nitrogen oxide absorption catalyst systems, particularly in diesel engines, are complex and inefficient due to sulfur poisoning, which affects NOx purification rates and requires intricate control of air/fuel ratios and regeneration of diesel particulate filters.
Innovation Solution
A method that determines desulfurization timing based on the number of DPF regenerations, maintains a desulfurization mode until a predetermined time, and adjusts the air/fuel ratio to control temperature, simplifying the process and reducing ECU memory usage, ensuring efficient sulfur removal without compromising fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional desulfurization method calculating SOx amount and determining deterioration rate is used, then desulfurization control can be performed, but the control process becomes complex and requires intricate management of PM trapping condition
Solution Approach 1:
The patent extracts the desulfurization control logic from the complex conventional method that required calculating SOx amounts and monitoring PM trapping conditions. Instead, it isolates only the essential parameter - DPF regeneration count - to trigger desulfurization, thereby simplifying the control process while maintaining effective sulfur removal from the LNT catalyst
Solution Approach 2:
The patent segments the desulfurization control into distinct operational phases: normal operation mode and desulfurization mode. The transition between modes is triggered by a simple counter of DPF regenerations reaching a predetermined value, creating clear separation between different control strategies and eliminating the need for continuous complex calculations
2Reliability
If DPF regeneration is performed frequently to maintain purification performance, then NOx purification rate is improved, but fuel consumption increases due to repeated regeneration cycles
Solution Approach 1:
The patent implements periodic desulfurization action triggered by counting DPF regeneration cycles. Instead of continuous or frequent regenerative operations, the system performs desulfurization at predetermined intervals based on regeneration count, allowing the LNT catalyst to maintain adequate sulfur levels for NOx storage while periodically removing excess sulfur that would degrade performance
Solution Approach 2:
The patent changes the operational parameter from continuous monitoring of sulfur levels to periodic intervention based on regeneration counting. By using the regeneration count as a trigger parameter, the system optimizes the timing of desulfurization events to balance NOx purification performance with fuel economy, avoiding unnecessary regeneration cycles
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively simplifies the desulfurization process, improves NOx purification performance, and reduces fuel consumption by optimizing desulfurization timing and temperature control, even with low sulfur diesel fuel.
Implementation Method 1
a Lean NOx Trap (LNT) of a diesel engine absorbs NOx of exhaust gas in a lean condition
Implementation Method 2
uses a rich condition of fuel to reduce NOx to N2 and O2
Implementation Method 3
the exhaust gas is heated and simultaneously the real air/fuel ratio is adjusted
Implementation Method 4
the particulate matters (PM) trapping condition of a diesel particulate filter (DPF)
Data Source
AI summary
A desulfurization method of a nitrogen oxide absorption catalyst when diesel is used may include determining how many times a regeneration of a diesel particulate filter (DPF) is completed, ending a DPF regeneration, if the number of times of the DPF regeneration reaches a predetermined value and entering into a desulfurization mode to desulfurize the DPF, ending the desulfurization mode after the desulfurization mode is performed for a predetermined time, and calculating a particulate matters (PM) amount that is trapped in the DPF after the desulfurization, compensating the trapped PM amount, and determining a time of the DPF regeneration. A desulfurization timing is determined based on the number of times that the DPF is regenerated to be able to simplify the desulfurization logic and also reduce the memory of ECU, when the LNT catalyst is poisoned by a small amount of sulfur included in exhaust gas.